New way of working beginning to rein in study (6)
I believe the answer is:
modern
'new' is the definition.
(I've seen this before)
'way of working beginning to rein in study' is the wordplay.
'way of working' becomes 'mo' (I've seen this in other clues).
'beginning to' indicates taking the first letters.
'in' means one lot of letters goes inside another.
'study' becomes 'den' (I've seen this before).
The initial letter of 'rein' is 'r'.
'r' placed inside 'den' is 'dern'.
'mo'+'dern'='MODERN'
(Other definitions for modern that I've seen before include "The very latest available" , "Up to date, of present times" , "Present-day" , "In history, the period or era since the Middle Ages" , "Of the present time or current fashion" .)